Method and device for drilling a channel

ABSTRACT

In a drilling method for creating a channel leading from surrounding soil into a shaft which is separated from the soil by a wall, a channel is drilled through the soil from a starting pit in the direction of the shaft using a first drill head. The first drill head continues to drill in this direction in order to create a breach in the wall, and a second drill head is then used in the shaft to widen the breach in the wall by drilling in the opposite direction with the second drill head.

BACKGROUND OF THE INVENTION

The invention relates to a method and a device for drilling a channelthat leads from the soil into a shaft surrounded by a wall, theinvention claiming priority of German patent application 102 57 392.1,to whose content reference is made.

Two different methods for installing house service connections aredescribed in DE 198 20 483 C1. First, a method is described in which acontrollable drill head is used to establish a channel for a houseservice connection from a starting pit, located outside the house, to atarget pit adjacent to the outside of the outer wall of the house. Thebreach in the outer wall is produced with a separate concrete drilldevice such as a drill hammer or drill saw.

DE 198 20 483 C1 describes an innovation in the form of a method inwhich a breach is first made through the outer wall from the directionof the inside of the house, using a drill bit to drill through theconcrete outer wall, and, after a change of tools, a channel for a houseservice connection is established, in the soil surrounding the house,using a drill head whose course is controlled.

Both methods are complicated. In one method, difficult excavation workhas to be carried out to form a target pit, and, in the second method,the entire equipment needed to drive the drill head forward on acontrolled course has to be accommodated in the house cellar.

SUMMARY OF THE INVENTION

Therefore, the object here is to make available a method which is easyto carry out and creates a channel leading from the soil into a shaftsurrounded by a wall, and also to make available a device suitable forthis method.

The invention is based on the concept of initially using a first drillhead to create a channel leading from the starting pit into the shaft,the drill head preferably being designed in such a way that it can bothcreate a channel in the soil and also breach a wall. In most cases, thebreach created in this way in the wall has, in its emergence area, anuneven and often arbitrary shape. For connection of channel pipes, it isgenerally necessary to re-work this breach in the wall. It is thereforeproposed, according to the invention, to replace the first drill headwith a second drill head on the drilling device used, and to drillcounter to the original direction of advance, at least for the area ofthe masonry. Thus, by suitable choice of the second drill head, a breachwith the desired shape and size can be created in the wall.

The method according to the invention further affords the advantage thata wall breach of small cross section can first of all be created in thewall by means of the first drill head. This breach can be created withless torque than in the case of a large breach. The subsequent wideningof the breach in the wall to a larger cross section can then likewise bedone with less torque. Thus, in the method according to the invention, adrilling device can be used which generates only a low maximum torque.

The method according to the invention also affords the advantage, forexample in use in sewage shafts, that a breach in the shaft wall can becreated without using an explosion-proof drill driver inside the shaft.The components introduced into the shaft can then pose no risk ofexplosion.

Breaches in shaft walls or room walls must in some cases be lined withspecific sealing materials. In most cases, the breach in the wall itselftherefore has to have a larger cross section than the pipe that is to beguided through the breach. With the method according to the invention,it is now possible to create an earth channel of small cross sectionadapted to the pipe to be passed through, and only to widen the wallbreach to the cross section adapted for the additional materials thatare to be introduced. In this way, it is possible to avoid forming theentire earth channel with a cross section larger than is necessary forthe pipe.

The present invention can be used to create a channel leading from thesoil into a shaft surrounded by a wall. A channel is understood asmeaning, in particular, any free space created in a more solidenvironment by drilling equipment. In particular, a channel is a freespace with a round cross section. The channel can be used to receivepipelines, cables and other elongate bodies. For example, reinforcementscan also be introduced into the channel. Likewise, the channel can befilled with a solid or solidifying material, for example in order tostrengthen the more solid environment.

A shaft is understood as meaning a free space which is surrounded by awall and which has channels leading to and away from it. In particular,a shaft is a connection shaft for pipelines, for example of the kindinstalled under streets, for example for removing waste water or forguiding gas conduits, telecommunication lines and other forms ofcommunication lines. A shaft within the meaning of this invention isalso understood, in particular, as including a space in a house, inparticular a cellar.

Soil is understood in the general sense of this word, but, for thepurposes of the present invention, also as an area underneath the soilsurface which has liquid or unfilled sections, and any solid, pourableor viscous material underneath the soil surface or in comparablecomposition and arrangement above the soil surface.

A wall is understood in particular as any piling of material createdspecifically to delimit the shaft. In particular, a wall is alsointended to include masonry formed from assembled individual parts, forexample stones. A wall may also be a room boundary cast from a materialsuch as concrete or plastic, for example.

For the purposes of illustrating this invention, a starting pit can alsobe a starting position on the soil surface.

According to the invention, the channel to be created is initiallyproduced from a starting pit using a first drill head which is drivenforward in the direction of the target shaft. The starting pit can inthis case be a specially excavated pit. However, the starting pit usedcan also be, for example, another shaft (starting shaft).

Particularly when drilling from a starting shaft, it may be expedientfirst of all to use another drill head to breach a wall surrounding saidshaft.

The creation of the channel by means of the first drill head takes placein particular according to the horizontal drilling methods that are wellknown in practice. In this case, the first drill head can be designed tomove forward by itself, for example, or to be driven forward by a rod.The first drill head can be a controllable drill head, for example withan asymmetrical drill head geometry and a control surface. It can bedesigned as a percussion drill head. The drill head preferably hasadapters for receiving a pipe that is to be introduced into the channelto be created, so that the pipe is drawn by the forwardly driven drillhead directly into the channel formed.

Forward drilling is particularly preferred, preferably using drill headswith a front cutter geometry.

On reaching the outer face of the wall surrounding the shaft, the drillhead is driven further forward and creates a breach through the masonry.

The first drill head can then be replaced or supplemented in the shaftby a second drill head. In the case of a drill head driven by rods, thefirst drill head can be released from the drill rod, and the seconddrill head can be connected to the rod. In this case, the second drillhead is preferably designed in such a way that it is suitable fordrilling by being pulled by a rod. The second drill head can then bedriven forward through the breach in the wall, counter to the directionin which the first drill head was driven through, and in so doing it isable to widen this breach. Widening is understood in particular as anenlargement of the cross section. However, widening, within the meaningof the invention, can also include the re-working of the peripheraledges of the breach in the wall. These edges can be smoothed bygrinding, or the shape of the breach in the wall can be re-worked orleveled out. This leveling-out is necessary, in particular, ifprefabricated connection elements are intended to be inserted into thebreach in the wall.

A core hole drill is preferably used as the second drill head. Thedrilling in the opposite direction with the second drill head ispreferably terminated upon reaching that surface of the wall locatedtoward the outside in relation to the interior of the shaft. In thisway, the drilling with the second drill can be reduced, thus resulting,in particular, in savings both in time and energy. However, the drillingwith the second drill head can be terminated even before reaching thatsurface of the wall located toward the outside in relation to theinterior of the shaft, for example if only that area of the wall breachlying to the inside of the shaft is to be re-worked. Likewise, thedrilling with the second drill head can also be terminated well behindthat surface of the wall located toward the outside in relation to theinterior of the shaft, for example if a connection element extendingbeyond the wall cross section is to be inserted into the breach in thewall.

The second drill head is recovered in a simple way by being guided backinto the shaft upon termination of the drilling with the second drillhead.

Targeted guidance of the drill head, in particular for aiming itprecisely at the point where the wall breach is to be created, isachieved if a transmitter on the first drill head and/or a furthertransmitter on the second drill head emits a position signal, and thedrilling parameters are regulated as a function of the position signalreceived by a receiver.

One drilling parameter is, in particular, the orientation of anasymmetrical drill head provided with a control surface.

The breach in the wall enlarged by the second drill head is preferablylined. In this way, for example, the pipe inserted into the shaft can beinsulated or can be connected to the wall. Moreover, connection piecesor prefabricated pipe attachments, for example, can be inserted into theenlarged breach in the wall.

According to the invention, a drilling system is also proposed, inparticular for carrying out the aforementioned method, comprising adrill slide, a drill rod and two drill heads, in which the first drillhead is designed to advance by being pushed by the rod, and the seconddrill head is designed to advance by being pulled by the rod, saidsecond drill head being designed to create a larger cross section of thedrilled hole.

According to the invention, a drill slide is understood in particular asany drive unit for a drill head designed to drive the drill headforward. In particular, a drill slide comprises a pusher unit which canbe connected to a free end of a drill rod section and with which thedrill rod section can be driven forward.

In order to provide a smooth edge when drilling through masonry, thesecond drill head is preferably designed with a large number of contactpoints on the drilling surface. Contact points are understood here aspoints on the drilling surface which are formed protruding therefrom andwhich are first to come into engagement with the material that is to bedrilled through. With an increasing number of these contact points, theforce applied by the drill head into the material to be drilled throughis distributed to a plurality of points. This prevents substantialforces being applied at a small number of points, which would otherwisecause spalling. Spalling is understood as meaning when, during drilling,large pieces of material split off from the material that is to bedrilled through.

BRIEF DESCRIPTION OF THE DRAWING

The invention is explained in more detail below with reference to adrawing. Illustrative embodiments of the invention are set out in thisdrawing, in which:

FIG. 1 shows a schematic representation of the means used to carry outthe method according to the invention,

FIG. 2 shows an enlarged representation of the detail indicated in FIG.1,

FIG. 3 shows a cutaway side view of core hole drilling as part of themethod according to the invention,

FIG. 4 shows a cutaway side view of a first method step in a furtherembodiment of the method according to the invention,

FIG. 5 shows a cutaway side view of a second method step in the furtherembodiment of the method according to the invention, and

FIG. 6 shows a cutaway side view of a third method step in the furtherembodiment of the method according to the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

A starting shaft 1 and a cellar 2, which represents the target shaft,are shown in FIG. 1. A drill slide 3 is arranged in the starting shaft1. With this drill slide 3, rod sections 4 are pushed into the channel 5created in the soil surrounding the starting shaft 1. The rod sections 4are connected to one another. As can be seen from FIG. 2, the frontmostrod section 4 is connected to a drill head 6. A torque can be applied tothe drill head 6 by the rod sections 4, and said drill head 6 can berotated about the forward drive axis.

To create the channel 5 between the starting shaft 1 and the cellar 2,the drill head is driven into the soil surrounding the starting shaft 1,by means of the rod sections 4 driven by the drill slide 3, and itcreates the channel 5 in said soil. Upon reaching the surface of thewall 7 located toward the outside in relation to the cellar, the drillhead 6 is driven further forward and creates the breach 8 in the wall asshown in FIG. 2. This breach exhibits irregularities of shape andspalling. Following the first breach of the wall 7, the drill head 6 isreplaced in the cellar by a drill head 9. The latter is designed tocreate a smooth drilled hole in a wall and is able to produce a wallbreach having a greater cross section than the wall breach created withthe drill head 6. This drill head 9 is guided by pulling the rods backin the direction of advance counter to that of the first drill head 6,and it creates, in the wall 7, a breach with a regular shape and withthe desired cross section (cf. FIG. 3).

Retaining the same reference numbers for identical components, FIGS. 4to 6 show a further embodiment of the method according to the invention.This embodiment is characterized by the fact that a core hole is alsodrilled in the starting shaft 1 in order to create a breach in the wall20 surrounding the starting shaft 1. This breach can be created with thesecond drill head 9.

The second drill head 9 is then replaced by the first drill head 6, anda pilot bore is created from the starting shaft 1 to a target shaft 21.In doing so, the drill head 6 creates a breach through the wall 22surrounding the target shaft 21 (cf. FIG. 5).

Following this, the drill head 6 is replaced in the target shaft 21 by adrill head 9. The latter is designed to create a smooth drilled hole ina wall and is able to produce a wall breach having a greater crosssection than the wall breach created with the drill head 6. This drillhead 9 is guided by pulling the rods back in the direction of advancecounter to that of the first drill head 6, and it creates, in the wall22, a breach with a regular shape and with the desired cross section(cf. FIG. 6).

1. A drilling method for creating an underground channel to a shaft,said method comprising the following steps: drilling a channel throughsoil from a starting pit in a direction of the shaft using a first drillhead, drilling through a wall of the shaft in said direction with thefirst drill head to create a breach in the wall, changing from the firstdrill head to a second drill head or drill arrangement in the shaft, andwidening the breach in the wall by drilling in the opposite directionwith the second drill head, wherein the widening step is terminated uponreaching a surface of the wall located outside in relation to aninterior of the shaft.
 2. The drilling method as claimed in claim 1,further comprising the step of retracting the second drill head into theshaft after termination of the widening step.
 3. The drilling method asclaimed in claim 1, further comprising the step of providing atransmitter on at least one of the first drill head and the second drillhead to emit a position signal to a receiver, and controlling drillingparameters as a function of the position signal received by thereceiver.
 4. The drilling method as claimed in claim 1, furthercomprising the step of lining the breach in the wall after the wideningstep.
 5. The method of claim 1 wherein the first drilling step involvesthe step of drilling a channel for a house service connection.